1. Field of the Invention
The present invention relates to a method for cleaning the glass surface of a surface light, a runway guide light, or a reflector by blasting a cleaning agent, and a system for carrying out the method.
2. Prior Art
A surface light, a runway guide light, or a reflector buried or installed on pavement and on road such as a landing strip, a road for tracks, a taxiway or in the vicinity thereof at some distance from each other often cannot perform its predetermined function due to an adhesion of automotive exhaust gas produced by traveling, stopping and starting on a track, adhesion of abrasion dust from tires, debris adhesion of calking compounds for waterproof processing a part of such a surface light, as well as adhesion or fouling of rain water and dust. Although dirt caused by an adhesion of rainwater and dust can be easily removed, it is not easy to completely remove a small dot-like spot from abrasion dust of a tire or calking compound stained (vaporized) onto the glass surface of a surface light.
For cleaning dust stained on the surface of such an object, an option to be applied is, in general, to sand blast for cleaning rust or polishing a surface of the works in a painting/plating shop. Alternatively, soft blast is used when an object is fragile. As an abrasive (cleaning agent, polishing agent) in a soft blast system, either bicarbonate (sodium bicarbonate) or dry ice (carbon dioxide) is used depending on the object and its purpose (Non-patent document 1). Namely, bicarbonate is used for pharmaceuticals and food additives and it is innocuous to the human body if it is blasted and diffused. Furthermore, dry ice used in this field is prepared by collecting and purifying carbonate dioxide discharged from a factory, so that it is noncombustible (digested material), and is sublimed into carbon dioxide to vaporize at ambient temperature. Therefore, it is practically innocuous.                Non-Patent Document 1: Sangyo Kikai, “Low-pollution bicarbonate blast apparatus”, 2001, August, pp 60-62.        